Effects of plant diversity on semiarid grassland stability depends on functional group composition and dynamics under N and P addition

• Published in: The Science of the total environment 2021-12, Vol.799, p.149482, Article 149482
• Main Authors: Chen, Zhifei, Xiong, Peifeng, Zhou, Junjie, Lai, Shuaibin, Jian, Chunxia, Xu, Weizhou, Xu, Bingcheng
• Format: Article
• Language: English
• Subjects: Fertilization; Functional group stability; Loess Plateau; Species asynchrony; Species richness; Temporal stability
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2021.149482

Exogenous fertilization could efficiently improve grassland productivity and promote grassland restoration. Increasing fertilization may profoundly affect community stability, whereas the underlying compensatory dynamics among functional groups in regulating grassland stability remain unclear. Three different grasslands, annuals forb (AF) community, perennial grass (PG) community and perennial forb (PF) community, on semiarid Loess Plateau were selected. We designed a 3-year split-plot experiment (main-plot: 0, 25, 50, and 100 kg N ha−1 yr−1; subplot: 0, 20, 40 and 80 kg P2O5 ha−1 yr−1) to explore how N and P addition affects community stability and its relationship with species richness, species asynchrony and functional group stability. Temporal stability differed largely between functional groups under N and P addition, perennial forbs or grasses had higher stability than perennial legumes or annuals and biennials. Decreased stability of PG and PF communities was primarily due to reduced species asynchrony under N addition alone, while it attributed to increased dominance of perennial legumes after P addition alone. 50 and 100 kg N ha−1 yr−1 combined with P addition significantly increased dominance of annuals and biennials, but decreased stability of annuals and biennials, which caused significant declines in stability of the three communities. Significant species richness decline induced by N and P addition only occurred in AF community, which suppressed AF community stability through reducing species asynchrony. AF community stability was regulated by additively negative effect of diversity decline and decreased annuals and biennials stability. Whereas, in PG and PF communities, nutrient-induced changes of functional groups stability were the main driver of community stability rather than diversity. Our study highlights the role of functional group composition and dynamics in regulating the effects of diversity on community stability and rational N and P combined addition was essential for conserving stability of different grasslands on semiarid Loess Plateau. [Display omitted] •Perennial forb or grass had higher stability than legume or annual and biennial.•High N and P increased annual and biennial dominance, but decreased its stability.•Diversity decline negatively affected community stability only in annual grassland.•Functional group shift was the main driver of perennial grassland stability.